Nature isn't outside of us, it is modified by humans

• Crosby shows this goes way back
• even areas that look natural to us have usually been logged and have species composition has changed significantly
  

Should we accept that and try to modify nature for good?

• new proposals for geoengineering such as the idea of putting sulfur in the atmosphere
• is there something wrong with this idea?  If so, what?
• don't know what is going to happen
• might create an imbalance in nature
• could be catastrophic if it doesn't work
• creating the symptoms and not the cause
• there is some level of meddling that is too much: "playing God" is a tricky argument to make because line changes
• technology often has unpredictable side effects plus watch out for scale (big interventions are riskier than small ones)
  
• beware of the technological fix--we don't have to worry because technology can solve our problems
• we are nervous about interfering with nature
• we can't been sure of the results
• we like to think that nature is separate, not something we control
  

Neo-Europes (places where the Europeans were successful in transforming the environment to look like home):

• Europeans displaced the native people
• changed the ecosystem to look more like Europe

So how did Europeans succeed in those places?

• how did they displace the natives--why is South Africa majority black but the U.S. is not majority Indian?
• European diseases killed off indigenous people in the Americas in large numbers (chapter 9)
  
• disease was a bigger problem for Europeans in Africa, particularly in the tropics (chapter 6)
  
• more Europeans migrated to the Americas (partly because they feared diseases in tropical areas and so fewer migrated say to Africa)
  
• Europeans had a bigger technological advantage in North America--Africans had iron

• Europeans brought their whole ecosystem with them--why was European agriculture so successful in (some but not all) new places?  And it wasn't just that what farmers planted grew--many plants spread faster than European settlement.
• you need a similar climate
• European plants took over in North America, not in Africa--this is the focus today
• how could European plants so successfully go wild--you can't say because they were better
• you have native plants that are well adapted to the environment--why can European plants out-compete them?
• quick answer--because the Europeans changed the environment
  

European plants were somehow better?  That doesn't make ecological sense.  European plants couldn't possibly be better adapted to the environment.  What were the advantages that European plants had?

What is a weed?

• it doesn't matter whether the plant is undesirable
  
• weeds are the plants that spread without human cultivation (eg. dandelions spread by wind-born seeds)
  
• weeds grow where the soil is disturbed--trees cut down, domestic animals eat native plants, etc.
• European plants succeeded because they were adapted to growing in the disturbed soil the Europeans created
  

European plants replaced native plants to a considerable extent

• 54-66% of the vegetation in California consists of European species
• clover and bluegrass spread faster than European settlers
• by 1920 only 20% of the vegetation of the pampa of Argentina was native plants
• non-native species are present in such large numbers in North America that they are a problem for anyone restoring ecosystems

These introduced plants are called non-indigenous or non-native species, and if they cause problems they are called invasive species.  How do they:  1. arrive, 2. survive, 3. thrive ?

Europeans plants were at first mostly brought on purpose (and weeds came with the crops):

• Europeans planted the crops they knew
• they wanted familiar foods and other products
• that was what there was a market for in Europe
• Johny Appleseed--planted apple seeds in the wild--produced apples not good to eat but you could make alcohol from them
• why is he a children's hero?
• he is doing something to benefit future generations
• he is transforming nature to make it friendlier to humans
• he is trying to make North America look more like Europe
  
• they wanted a familiar-looking landscape around them
• they brought their own ornamental plants too
• and honeybees to pollinate their crops
  

Why did European plants survive and thrive in the neo-Europes and not vice-versa?
this surprising and needs to be explained

• the exchange was not symmetrical: European plants spread in the neo-Europes but, in general, plants from the neo-Europes did not spread (except where cultivated) in Europe
• why is it not the same in both directions
  
• were European plants better?  no--they were adapted to the European environment
• the European environment involved:
• lots of agriculture--usually plowed every year
  
• no undisturbed wild land left
• lots of grazing animals on the land that wasn't planted in crops
  

• the European plants were better suited to an environment disturbed by humans and their animals
  
• plants in the Americas weren't evolved to survive heavy grazing, so cattle and sheep displaced native plants
  
• European plants had evolved to live in land disturbed by agriculture--weeds--they like the environment when whatever was growing there has been removed and the soil is exposed
  
• they were plants that like to grow where the soil has been disturbed by
  
• agriculture
• deforestation--cutting down trees lets in more sun and opens up the soil
  
• pigs (and cattle and sheep)

European plants became weeds and took over in the neo-Europes, why didn't imported plants become a significant problem in Europe?

• the plants of the Americas and Australia preferred undisturbed environments, which were rare in Europe
• a few plants from the Americans became important as crops in Europe
  
• most important what we call corn, known in Europe as maize (in Europe "corn" is a general term for any kind of grain)
• also potatoes and tomatoes (which were thought at first to be poisonous)
  
• peanuts and manioc became important in Africa and sweet potatoes in Asia
• crops were a fairly even exchange, unlike plants in the wild
• few plants from the neo-Europes could do well in the disturbed environment of Europe
  

European plants were more adapted to disturbed soil and the Europeans disturbed the soil
European plants were more aggressive in some situations (able to spread quickly)

• is this saying European plants were better?
• no, but they were better adapted for living on land disturbed by agriculture
• the ability to spread quickly is most useful when the land is disturbed
  
• consider French explorers in the Pacific in the 1790s
• when they arrived someplace new they would plant a garden of European plants as a scientific experiment and leave European animals
• they were interested in adaptation (which they called acclimatization)
• the plants did not do well in the absences of settlers
  
• European plants were adapted to live alongside of farming and grazing
• European plants succeeded because they were adapted to the conditions that Europeans created
• the Europeans changed the environment in ways that favored their plants
• Europeans were able to change nature on a very large scale